When selecting greedy package inside depgraph._greedy_slots(), make sure
the selected packages have the same cp as the highest selected version.
(trunk r12490)

svn path=/main/branches/2.1.6/; revision=12491
diff --git a/pym/_emerge/__init__.py b/pym/_emerge/__init__.py
index 5a00510..9d2d62d 100644
--- a/pym/_emerge/__init__.py
+++ b/pym/_emerge/__init__.py
@@ -5648,7 +5648,8 @@
 			slot = slots.pop()
 			slot_atom = portage.dep.Atom("%s:%s" % (highest_pkg.cp, slot))
 			pkg, in_graph = self._select_package(root_config.root, slot_atom)
-			if pkg is not None and pkg < highest_pkg:
+			if pkg is not None and \
+				pkg.cp == highest_pkg.cp and pkg < highest_pkg:
 				greedy_pkgs.append(pkg)
 		if not greedy_pkgs:
 			return []